Process for beneficiation of nonmagnetic material

ABSTRACT

A novel process for beneficiating nonmagnetic ores and other source materials, particularly lean iron ores, wherein paramagnetic material in such ores is given a temporary positive magnetic susceptibility, passed within the field of a moving permanent magnet system before the material decays to its natural state, and the so activated paramagnetic substance separated by deflection toward the magnet system and recovered from nondeflected diamagnetic material in admixture therewith.

United States Patent References Cited UNITED STATES PATENTS 460.962l0/l89l Gouyard 209/219 Inventor Joseph R. Hradel 6482 South MissionRoad, Mount Pleasant. Mich. 48858 Appl. No. 794,103

Filed .Ian. 27, 1969 Patented July 27, 1971 PROCESS FOR BENEFICIATION OFNONMAGNETIC MATERIAL 6 Claims, 1 Drawing Fig.

Int. Cl B03c 1/00 Field of Search A. 209/39. 40,

2l9,2l4,2l5,2l2.2l3,232,220,2l8,478,216. 227. 131.1. 3l4,8,8.l;2l0/222.223

2,325.149 7/l943 Rakowsky t. 209/232 X 2,71 1,249 6/l955 Laurila 209/2192,748,940 6/1956 Roth 209/219 3,294,237 l2/l966 Weston 20 /227 X3,372,803 3/l968 De Lisle 209/214 X 3,289.836 l2/l966 Weston 209/214Primary Examiner- Frank W. Lutter Assistant Examiner- Robert HalperAttorney-C. Kenneth Bjork ABSTRACT: A novel process for beneficiatingnonmagnetic ores and other source materials, particularly lean ironores, wherein paramagnetic material in such ores is given a temporarypositive magnetic susceptibility, passed within the field of a movingpermanent magnet system before the material decays to its natural state,and the so activated paramagnetic substance separated by deflectiontoward the magnet system and recovered from nondeflected diamagneticmaterial in admixture therewith.

PROCESS FOR BENEFICIATION OF NONMAGNETIC MATERIAL The present inventionrelates to a novel process for separating paramagnetic material fromdiamagnetic material and more particularly is concerned with a novelprocess for beneficiating ores which are not naturally magnetic such as,for example, lean nonmagnetic iron ores including tailings fromconventional ore processing, to recover the bulk of the useful anddesired metal values therefrom.

Current ore beneficiating employing electromagnetic and magneticseparatory techniques as exemplified by US. Patents Nos. 2,954,122,2,325,l49 and 2,558,635 are applicable only in separating and recoveringfrom ore bodies the naturally magnetic portions of the ore or thosemetal values which can be given a prolonged magnetism from an inducedelectromagnetic force and which retain this magnetism until the materialis demagnetized by passage through an opposing electric coil or otherdemagnetizing means.

Many lean ores, particularly ferrous ores, which are abundantly andwidely distributed throughout the world are not presently mined becausethey are not susceptible to beneficiation by such known techniques;Additionally, nonmagnetic tailings resulting from beneficiation ofmagnetic ores contain a large percentage of iron values which at presentare discarded because these values are unresponsive to separation bymagnetic beneficiation techniques now practiced.

Now, unexpectedly l have discovered a novel process for separating andrecovering nonmagnetic but paramagnetic metal values, particularlynonmagnetic iron values, form ores and other source materials includingtailings from gangues resulting from conventional iron separatorytechniques.

It is a principal object of the present invention to provide a novelprocess for separating and recovering paramagnetic materials which arenonmagnetic, i.e. are not naturally magnetic or will not hold anyinduced magnetism for a prolonged period of time, from diamagneticmaterials.

It is also an object of the present invention to provide a novel processfor beneficiating and recovering iron values from source materials whichdo not respond to and cannot be used in conventional magneticbeneficiating techniques.

These and other objects and advantages readily will become apparent fromthe detailed description presented hereinafter when read in accordancewith the FIGURE of the appended drawing which shows a schematic flowdiagram of one embodiment of the process of the present invention.

in general the process of the present invention comprises providing aparticulate nonmagnetic source material which cannot be renderedpermanently magnetic but which contains at least one paramagneticsubstance to be separated and recovered. This source material is passedthrough or within the effective range of an electric coil therebyupsetting said material and imparting a temporary positive magneticsusceptibility to said paramagnetic material and a negative magneticsusceptibility to any diamagnetic material present therein. The so upsetmaterial is brought within the field of a moving permanent magnet systembefore the positive magnetic suscepti bility in the paramagneticmaterial decays to a state where said paramagnetic material is notattracted by said magnetic system thereby deflecting and separating saidparamagnetic material from diamagnetic materials present which receiveda negative magnetic susceptibility from exposure to said coil. The termupset for the purpose of this specification is defined as the act ofdisturbing the electromagnetic equilibrium of a paramagnetic ordiamagnetic material form its natural state by electromagnetic means.

This method is particularly adapted for use in separating and recoveringiron values from nonmagnetic ore bodies and other source materials ashas been pointed out hereinbefore. Representative examples of such ironsource materials are iron ores containing such paramagnetic materials asthe spicu- -lar and cherty hematites consisting largely of Fe embeddedin diamagnetic gangues of the nature of silica as are found in the uppercentral United States. These materials, although lean, represent aneconomically beneficiable reserve beyond that which is currently beingrecovered if consideration is given to the fact that differences inmagnetic susceptibility values constitute a basis for separation of ironcompounds form their gangues. Other iron bearing compounds are containedin lean ores such as mascarite, the nonmagnetic fraction of pyriticmagnetite, pyrite, siderite, limonite, and the green potassium ironsilicate as well as the tailings from previous beneficiations of theseores. All of these are available in abundant quantities in various partsof the United States as well as throughout the world. Hereinafter theterm ore" as used in the specification will mean and include bothnaturally occurring nonmagnetic ores such as the lean ores exemplifiedhereinbefore as well as tailings and other source materials resultingfrom prior beneficiation or separatory processes.

Ordinarily in carrying out the practice of the present invention, an oreis crushed or ground to break it down and effect separation of theparamagnetic metal values from diamagnetic gangue materials. Usually theore is crushed to pass a number 60 US. Standard Sieve, and particulatematerials ranging from 60 to 325 mesh or finer have been found to beparticularly suited to the practice of the present invention. Coarserparticles can be employed, if desired, provided that effective physicalseparation from gangue material is realized.

The crushed ore is subjected to the influence of an energized electriccoil of sufficient energy and for a period of time to establish atemporary positive magnetic susceptibility in the paramagnetic materialspresent therein and a negative magnetic susceptibility in anydiamagnetic substances which may be in admixture therewith. Theresulting positive and negative magnetic susceptibilities in the upsetmaterial are not per manent or even prolonged in duration but are ofshort duration, i.e. exist from less than a second to a minute or moreand ordinarily have a maximum of about several minutes.

The so upset ore is passed within the field of at least one rotatingpermanent magnet, usually a plurality of such magnets, before thepositive magnetic susceptibility given to the paramagnetic material inthe ore decays to a state where the material becomes unresponsive to thepermanent magnet system. One particularly effective system employs aplurality of magnets mounted on a moving frame, for example, a rotatingdrum. This system has been found to be of a high utility since therotation of the magnets serves to substantially eliminate undesirablebuildup of the paramagnetic material, even for a short period of time,on the magnets or clogging of the deflection chamber, adjacent theretoif such is employed in the apparatus for carrying out the process.

Optimum in-separation of the active paramagnetic material fromdiamagnetic material in admixture therewith is realized by utilizing aminimum period of time between upset and subjection to the magneticfield. The sooner the material is brought under the influence of thepermanent magnet the more positive and greater will be the deflectionand consequent separation of the desired paramagnetic product. Asindicated hereinbefore, at a maximum about one minute is employed andpreferably this time is from less than a second up to several seconds.

The deflected paramagnetic product after it is passed beyondthe magneticfield is collected separately from the nondeflected diamagneticbyproduct. In some instances it is to be understood that thenondeflected diamagnetic material may be the desired product or bothmaterials may be of interest.

Conveniently, the starting material is passed by gravity flow through anenergizing coil past the magnet system and the separated materialsfurther passed into a collection system. Alternatively, a liquid pumpingsystem for handling an ore in aqueous suspension can be employed. Thislatter procedure assures that the throughput rates of the ore can becontrolled by the pumping rates thus reducing to a minimum, e.g. afraction of a second, the time required to transport the ore between theenergized upset coil and the permanent magnet system. This provides theadded advantage that the flow rate through the coil can be adjusted andmaintained to be the same as the flow rate past the moving permanentmagnets thereby serving to further control the product distribution andeliminate congestion in the vicinity of the magnets and/or thecollectors.

The collected paramagnetic product can be recovered and used directly,or. in the case of iron ores, can be further processed concentrated andotherwise converted, for use in particular situations.

Alternating current in the upset coil is preferred over direct currentin that the former offers the further advantage that minimum clogging orbuildup in the core is found. This is particularly true when utilizingsilicate and sulfur based iron ores, e.g. marcasite, pyrite, and pyritichematite. Oxide and hydroxide ores are less prone to clogging and adirect current source is just as effective as an alternating current forthese latter materials.

One embodiment of a hydraulic system for carrying out the presentprocess is shown schematically in the FIGURE of the drawing. in thisembodiment, a mixing-holding-feed hopper l0, usually fitted with a valvenear its bottom, is provided. This hopper is connected at its bottom tothe top of a flow through electrically powered upset coil 12. The bottomof the hopper 10 is connected to the top ofa deflection chamber 14. Thischamber I4 is curved along one side of its length 5 so as to coincidegenerally with the contour of a cylindrical frame 16 holding a pluralityof permanent magnets 18. Preferably the wall of the chamber adjacent themagnet system is in close proximity to this system. The bottom ofchamber 14 is fitted with a divider 20 which serves to directdiamagnetic byproduct to a gangue thickener collecting vessel 22 andparamagnetic product to a product collector 24. Conveniently the intakeat the top of the deflection chamber has a cross-sectional area aboutequal to that of the two discharge outlets of the bottom of thischamber. Ordinarily, the cross-sectional area of each of the dischargeoutlets is slightly smaller than 0.5 that of the intake. This, in turn,provides for a slight back pressure in the system thereby providingduring operation cleaner cuts in a more rapid manner with less recycle.Each of the containers 22 and 24 is fitted respectively with a conduit26 and 28 which fed to a common transport conduit 30. Conduit 30 in turnis connected through pump 32 to hopper 10. The hopper 10 is fitted withan ore supply conduit 34 which extends to an ore supply reservoir 36.Conduit 30 can be fitted with a makeup conduit 38 connected to a fluidsupply source (not shown).

in operation of this system, in one embodiment a ground ore and a liquidcarrier, usually water, with or without additional agents such as, forexample surfactants, are blended in the hopper 10 to provide a slurry ofpredetermined consistency. This slurry is controllably fed through thecoil 12 where the ore is upset and the paramagnetic material of the oreis given a temporary positive magnetic susceptibility. The so upset orecontaining slurry is directed to the inlet of the deflecting chamber 14.As the slurry passes through this chamber 14 and past the revolvingmagnets 18 the paramagnetic material is deflected towards and attractedby the magnets. This material follows the contour of the chamberadjacent the magnets 18 and drops form outlets at the bottom of thecollection chamber 14 into the collector 24. The nondeflecteddiamagnetic material falls directly into the gangue collector 22.

The materials are settled in their respective collectors, and recoveredby conventional means. The supernatant liquid is removed form thecollectors 22 and 24 by conduits 26 and 28 being pumped into conduit 30and returned to hopper 10 for reuse. Such reuse of the carrier liquidprovides for the maximum of product recovery as any useful valuesretained in the liquid will be again passed through the beneficiationprocess. The diamagnetic gangue can be recycled for furtherbeneficiation if desired.

Alternatively, the hydraulic conduit and pumping system can beeliminated and dry material by gravity or force fed from the hopperthrough the energizing coil. passed through the field of the movingpermanent magnet system and on intc the collection bins.

Other modifications can be employed. Also electrical assemblies,mechanical and hydraulic systems suitable for use in the practice of theinvention for any particular applications are within the knowledge ofone skilled in the art to which this process pertains.

The following examples will serve to further illustrate the presentinvention but are not meant to limit it thereto.

EXAMPLE 1.

Nonmagnetic cherty hematite tailings or spicular hematite having variousamounts of iron (expressed as percent Fe 0 and ground to pass a 60 meshU.S. Standard Sieve but be retained on a 325 mesh sieve were passed drythrough a 2,500 ohm upset coil energized by an alternating currentcircuit and operating at 16 volts. These tailings were discardnonmagnetic gangue products resulting from conventional magnetic orebeneficiation processes.

Each of the upset materials was retained for a predetermined period oftime and then passed within the field of a revolving permanent magnetsystem. The amount of sample attraction, i.e. beneficiation of the ironsource, by the permanent magnets was determined.

The results of this study which was designed to illustrate theoperability of the present process for beneficiating paramagnetic, butnot permanently magnetic, materials from diamagnetic substances admixedtherewith are summarized in table I. These results also show thecriticality of passing the upset material within the field of thepermanent magnet system within a short period after being activated bythe upset coil to achieve optimum in beneficiation.

TABLE I Percent sample fraction in beneficiate (time in min. after beingupset) Iron source material percent iron Time between upset and passagethrough magnet field.

EXAMPLE 2.

Using a separatory apparatus of general construction similar as thatshown in the FIGURE of the drawing, an aqueous slurry of a chertyhematite tailing (one kilogram of iron source material) and having aknown iron content (expressed as percent Fe 0 and ground to apredetermined particle size range was pumped through an alternatingcurrent (l6 volts) energized upset coil (2,500 ohms). The resultingupset iron source material was pumped into a deflection chamber whichwas adjacent a plurality of permanent magnets mounted on a revolvingdrum. The time between upset and passing of a given particle of the ironsource material in the field of the magnets was a fraction of a secondat a maximum. The product materials were collected in separate bins, thegangue material being recycled for a total treating time of fiveminutes. After this period of time, the beneficiated iron product wasrecovered and the iron content determined by conventional analyticaltechniques.

The results of this study are summarized in table ll which follows.

TABLE II Beneficiated product Ore pat'ticulation (mesh sieve) Fe in Wt.Iron feed percent content Gangue Run Retained (percent of (percent(percent No. Passed 0n F9103) feed F8203) F0203) Dry iron sourcematerials of particle size ranging from about 60 to 325 mesh and whichhad been freed of all naturally magnetic materials were passed bygravity feed through Various modifications can be made in the presentinvention without departing from the spirit or scope thereof for it isunderstood that l limit myself only as defined in the appended claims Ian upset coil of 7,500 ohms and activated by alternating curl Clalmlrent at a potentlal of [6 volts. The upset material was passed 1 Aprocess for Separating nonmagnetic paramagnetic through 'f l f arevolvmg magnet material from diamagnetic material which comprises:system In a Single P the P between of a. providing a finely dividedmixture of paramagnetic and P and field Q belng 'f l0 diamagneticmaterial, said mixture being further characseconds. The diamagneticmaterials. i.e. tailings, which were terized as being not naturallymagnetic, not named by the magnet system were Collected Separately b.passing said mixture within the effective range of an elecfrom theparamagnetic tron product, Le. beneficlate. that had icaIly energizedupset coil thereby upsetting aid mix. received a temporary posltlvcmagnetic Susceptibility and was t re and imparting a temporary positivemagnetic suscepdeficc ed t war s th m gn Thi latter material W35tibility to said paramagnetic material of said mixture and separatedfrom the magnetic field and recovered. The iron a negative magneticsusceptibility to said diamagnetic contents of the recovered fractionswere determined by conmaterial of said mixture, said temporary positiveand ventional analytical techniques. negative magnetic susceptibilitiesexisting in said materi- The results of a number of runs with variousiron source als for a period of time of from less than i second up tomaterials are summarized in table ill. about several minutes TABLE IIIPercent of iron compounds Percent iron Percent compounds recovery In RunNo. Iron source material Nature otlron values in loading from loadingbeneficiate stock stock product In tails l. Pyritlc hematite....FeS-FezOr lusterous..... 88. 4 89. 3 90. 0 25. 5 2. Marcasite FeSzyellow 66. 0 87. 7 70. 0 37. 0 3.. yrite...... FeS black 96. 5 98. 8 98.0 30.0 4.. Siderite FeCO; yellow 55.0 34.0 95.0 35.0 5.. KFesillcateGreen ore 54. 1 21. 3 70. 0 50.0 6.. Limonite Fe(OH); yellow 67. 5 22. 695. 0 60. 0 7.. .do ..do 47. 2 17. 7 80. 0 30. O 8.. Cherty sideriteFeCO; red 60. 0 30. O 95. 0 45. 0 9.... Hematite F620] splcular-..- 78.056. 8 70. 0 25.0 10... ..do F920: ch tty 72. 0 69. 3 90. 0 37. 0 l1..do. d0 52.0 38.0 60.0 20.0 1 d0 do 25.0 52.0 35.0 10.0

EXAMPLE 4' c. bringing the so upset mixture within the field ofa movingA number of studies were run to determine the current consumption forvarious diamagnetic and paramagnetic substances in an upset coil. Forthese studies, a coil of2,500 ohms at a predetermined temperature wasenergized by alternating current of 16 volts potential and a core of apredetermined material placed within the coil. The time for consumptionof a watt-hour of energy was measured. The results of these runs aresummarized in table IV. The marked differences iii power consumptionrates for the various materials as shown in the table indicates the coilinfluences a given materialin a specific manner, Le. gives it atemporary positive or negative susceptibility, and thus provides thebasis for the present process for recovering useful paramagneticmaterials from nonmagnetic source materials.

permanent magnet system within the time interval that the paramagneticmaterial retains its temporary positive magnetic susceptibility and isattracted and deflected towards said magnet system, and

d. recovering the so deflected paramagnetic material.

2. The process as defined in claim 1 wherein the upset material ispassed through said electrically energized upset coil.

3. The process as defined in claim 2 wherein the upset mixture is passedadjacent to a rotating system of a plurality of permanent magnets.

4. The process as defined in claim 3 wherein the mixture comprisesnonmagnetic iron source material and the time interval between upset andpassage within the field of said mov- TABLE ing magnet system rangesfrom less than one second to about temp.. Core material Sec/watt hr. onemmute' I l v Hematite A L 605 5. The process as defined in claim 4 wheren the iron source 5 Hematite p, l 2 5 material is a lean iron ore ortatlings resulting from conven- 62 Hematite C 1 tional ore processingoperations, said material being substan- {85 1 tially free fromnaturally magnetic substances and said materigg i z gz 8g; al rangingfrom about 60 to about 325 mesh U.S. Standard 66 Zn dustji 594 Sieve. II 2 6 iiii gtik'die 22 6. The process as defined in claim 5 wherein theiron source 56 Zirconium granula material is provided as an aqueousslurry and including the 2i Cuo 7 65 step of pumping said slurry throughsaid energized coil and ad- 50 873 l Designates item to be paramagnetic.7 Separate samples from different sources.

jacent said rotating system of permanent magnets.

UNITED STATES PATENT OFFICE Patent No.

Dated July 27, 1971 Inventor(s) Joseph R. Hradel It is certified thaterror appears in the aboveiderit1f1d patent and that said Letters Patentare hereby corrected as shown below:

Column 1, line 11,

Column 1, line 67,

Oolumn 3, line 26,

Column 3, line #5,

Column 3, line 62,

change form" to --fromdelete the letter "s" before change "is fitted"insert --a.lso-- "form" to --from-- Signed and sealed this 1 8th day ofJanuary 1 972.

(SEAL) Attest:

EDWARD M.FLETCHER,

Attesting Officer ROBERT GO'I'TSCHALK Ac ting Commissioner of Patents

1. A process for separating nonmagnetic paramagnetic material fromdiamagnetic material which comprises: a. providing a finely dividedmixture of paramagnetic and diamagnetic material, said mixture beingfurther characterized as being not naturally magnetic, b. passing saidmixture within the effective range of an electrically energized upsetcoil thereby upsetting said mixture and imparting a temporary positivemagnetic susceptibility to said paramagnetic material of said mixtureand a negative magnetic susceptibility to said diamagnetic material ofsaid mixture, said temporary positive and negative magneticsusceptibilities existing in said materials for a period of time of fromless than 1 second up to about several minutes c. bringing the so upsetmixture within the field of a moving permanent magnet system within thetime interval that the paramagnetic material retains its temporarypositive magnetic susceptibility and is attracted and deflected towardssaid magnet system, and d. recovering the so deflected paramagneticmaterial.
 2. The process as defined in claim 1 wherein the upSetmaterial is passed through said electrically energized upset coil. 3.The process as defined in claim 2 wherein the upset mixture is passedadjacent to a rotating system of a plurality of permanent magnets. 4.The process as defined in claim 3 wherein the mixture comprisesnonmagnetic iron source material and the time interval between upset andpassage within the field of said moving magnet system ranges from lessthan one second to about one minute.
 5. The process as defined in claim4 wherein the iron source material is a lean iron ore or tailingsresulting from conventional ore processing operations, said materialbeing substantially free from naturally magnetic substances and saidmaterial ranging from about 60 to about 325 mesh U.S. Standard Sieve. 6.The process as defined in claim 5 wherein the iron source material isprovided as an aqueous slurry and including the step of pumping saidslurry through said energized coil and adjacent said rotating system ofpermanent magnets.